1Thomas Jefferson to Joel Yancey, 25 December 1819 (Jefferson Papers)
Poplar Forest (TJ’s Bedford Co. estate); gypsum used as fertilizer at [index entry]
2Thomas Jefferson to Joel Yancey, 11 January 1818 (Jefferson Papers)
Poplar Forest (TJ’s Bedford Co. estate); gypsum used as fertilizer at [index entry]
3Thomas Jefferson to George Washington Jeffreys, 3 March 1817 (Jefferson Papers)
Poplar Forest (TJ’s Bedford Co. estate); gypsum used as fertilizer at [index entry]
4Thomas Jefferson to Joel Yancey, 7 June 1815 (Jefferson Papers)
Poplar Forest (TJ’s Bedford Co. estate); gypsum used as fertilizer at [index entry]